Processing facilities are often managed using process control systems. Example processing facilities include chemical, pharmaceutical, paper, and petrochemical production plants. Among other operations, process control systems typically interact with and control industrial equipment in the processing facilities, such as equipment used to produce chemical, pharmaceutical, paper, or petrochemical products.
Process control systems routinely include wireless components, such as wireless sensor networks that provide measurement data to process controllers. A typical wireless sensor network often includes battery-powered sensor devices and other battery-powered devices.
A significant obstacle to the adoption of wireless devices in process control systems and other systems is the potential failure of the wireless devices due to loss of battery power. This is often a result of maintenance personnel failing to service the wireless devices properly, where proper maintenance includes timely battery replacement. This problem is exacerbated by the fact that battery power in wireless devices is often not consumed at the same rate by all wireless devices in a system. This could be due to different usage patterns of the devices or other factors. For example, wireless devices requiring frequent communication typically also require more-frequent battery replacement. However, the proper battery replacement schedule for a wireless device often cannot be determined when the wireless device is installed.
A number of techniques have been used to attempt to determine the proper battery replacement schedule for wireless devices after installation. Some techniques have used formulas based on an average expected transmitter behavior of a wireless device and an average shelf life of a battery. Other techniques have relied on indicators showing low battery power based on the output voltage of the battery. Each of these techniques has its shortcomings, however, which can result in premature or overdue replacement of batteries in wireless devices.